Directional antenna



May 12, 1942- E. METscHl.

DIRECTIONAL ANTENNA Filed Nov. 9, 1939 Patented May 12, 1942 NITEDSTATES DIRECTINAL ANTENNA Application November 9, 1939, Serial No.303,520

In G

1 Claim.

Directional antennae intended for very short waves, such as ultra shortWaves and decirneter waves, are known which are composed of a number ofdipoles arranged in line to constitute a single antenna.

The invention relates to antenna structures of the kind comprising anumber of antennae composed in this way, and it is mainly concerned withthe provision of means by which these antennae are secured together.

In the accompanying drawing, Fig. 1 is a dagrammatic perspective view ofan antenna of known type, Fig. 2 is a diagrammatic perspective viewwhich shows one embodiment of the invention, Fig. 3 is a plan view ofthe arrangement represented in Fig. 2.

Fig. 1 shows tubular dipoles I, 2, 3, 4 arranged in line and containingconductors 5, 6, l, 8. These conductors and dipoles are interconnectedalternately, that is to say, conductor 5 is joined to dipole 2,conductor 6 joined to the dipoles I, 3, conductor 1 joined to thedipoles 2, 4, while conductor 8 is -connected to dipole 3. The dipolesare each half a wavelength long. The distribution of potentials isrepresented by curves 9, I0,

II, I2 which show that there is a potential node in the middle of eachdipole. With such an antenna positioned vertically the directive diagramthereof is circular in the horizontal plane while in the vertical planea sharp concentration of the lines of force is effected by the antennabeing:

excited in harmonics.

In order to obtain an additional directive effect it will be necessaryt0 employ a number of antennae of the kind represented in Fig. 1. Theseantennae have to be arranged aside each other and at predetermineddistances apart while -re- 'quiring to be interrelated by certain phaseconditions. All these antennae may be fed, but it is possible also tofeed only one antenna, the other ermany November 9, 1938 (-Cl. Z50-33)held in position by braces I9, 20, 2|, 22,'xed at the potential nodes ofthe dipoles I, 2, 3, 4 of which each antenna is composed.

In this Way an antenna system of mechanic uniformity can be constructedwith the .aid of simple means. It is not necessary to have the bracesI9, 20, 2l, 22 made of high-grade insulating material. Inferiorinsulating material may be used instead or the braces may be made ofmetal. For instance, they may be cast members. As the braces are fixedat the potential nodes no currents will ow between the antennae I3, I4,I5, I6.

Systems as provided by the invention may comprise any suitable number ofantennae and these may `consist of any suitable number of dipoles. It isimmaterialalso whether they are fed or are arranged to act as merereflectors. Furthermore, the novel arrangement is adapted to serveeither for transmitting or for receiving. Moreover, the invention is notrestricted to the use of component dipoles of the kind/comprising innerconductors and tubular outer conductors interconnected at their joints.However, it is necessary for the voltage distribution to be such thatthere are potential nodes at which the said braces are fastened to thedipoles. The antenna system as a whole may be positioned vertically orhorizontally. Preferably, it is arranged as a freely supportedstructure.

What is claimed is A rigid unitary antenna structure for shorty Y andhorizontal spacingy of all the dipoles is per-4 manently maintained. Y e

EMIL METSCHL.

